How Instagram, WhatsApp, Uber & Netflix Would Be Built Today Using Expo Router

Topics to Cover

1. How modern large-scale mobile apps are structured

2. Why architecture matters in React Native applications

3. Folder architecture using Expo Router

4. Feature-based separation in large applications

5. Navigation architecture for scalable apps

6. Authentication flow architecture

7. State management strategies for large apps

8. API handling and networking layers

9. Realtime systems:

   • Chat systems

   • Live updates

   • Ride tracking

10. Offline-first support and caching

11. App startup optimization techniques

12. Performance considerations in production apps

13. Shared layouts and nested routing in Expo Router

14. Scalability challenges in apps like:

• Instagram

• WhatsApp

• Uber

• Netflix

1. Tradeoffs and architectural decisions teams make at scale

Suggestions

1. Start by explaining why simple folder structures fail at scale

2. Focus on architecture thinking rather than UI cloning

3. Use each company app as a learning example:

   • Instagram → feeds and media

   • WhatsApp → realtime messaging

   • Uber → maps and live location

   • Netflix → heavy content delivery

4. Explain how Expo Router helps organize complex navigation

5. Introduce feature-based architecture early

6. Compare small-app thinking vs production engineering thinking

7. Keep discussion framework-agnostic where possible

8. Avoid deep backend implementation details

9. Emphasize maintainability, scalability, and developer experience

Diagram Ideas

1. Production-grade Expo Router folder structure

2. Authentication flow with protected routes

3. Feature-based architecture visualization

4. Realtime messaging architecture flow

5. API layer + state management flow

6. App startup lifecycle optimization diagram

7. Offline cache synchronization flow

8. Navigation hierarchy for large applications